# US 12,760,895 B2 · Dilution passages for combustor of a gas turbine engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,760,895 B2 - Document ID: US12760895B2 - Status: Granted - Kind: B2 - Application number: 18/104,685 - Filed: 2023-02-01 - Published: 2024-08-01 - Granted: 2026-10-13 - Earliest claimed: 2023-02-01 - Assignees: Rtx Corporation - Applicants: RTX Corporation - Inventors: Ian Walters; Baris A. Sen; Manuel J. Hernandez; Scott A. Liljenberg; Stephen K. Kramer - Web page: https://patentgrep.com/patent/US12760895B2 ## CPC - F23R 3/06: Arrangement of apertures along the flame tube - F23R 3/002: {Wall structures (F23R3/02 and F23R3/007 take precedence)} - F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16) ## Abstract A wall assembly for use in a combustor of a gas turbine engine, the wall assembly including: a support shell; a liner panel; and an annular grommet extending from the liner panel, the annular grommet defining a dilution passage and the annular grommet extends through an opening in the support shell when the support shell and the liner panel are secured to each other, the annular grommet having a top portion that defines a portion of a periphery of the dilution opening; and a backstop extending from the top portion of the annular grommet, the backstop defining another portion of the periphery of the dilution passage and the backstop extending through and above the opening in the support shell when the liner panel is secured to the support shell. ## Claims ### Claim 1 A wall assembly for use in a combustor of a gas turbine engine, the wall assembly comprising: a support shell; a liner panel, the liner panel being separately secured to the support shell; and an annular grommet extending from the liner panel, the annular grommet defining a dilution passage having a dilution passage axis and the annular grommet extends through an opening in the support shell when the support shell and the liner panel are secured to each other, the annular grommet having a top portion that defines a portion of a periphery of the dilution passage; and a backstop extending from the top portion of the annular grommet, the backstop defining another portion of the periphery of the dilution passage and the backstop extending through and above the opening in the support shell when the liner panel is secured to the support shell, wherein a portion of an inner wall of the annular grommet includes a linearly converging contoured inner wall portion that extends from the top portion to a bottom portion of the annular grommet, the bottom portion being opposite the top portion and located at a hot side of the liner panel, the linearly converging contoured inner wall portion has a first inner periphery defining a portion of a first cross-sectional area of the dilution passage and a second inner periphery defining a portion of a second cross-sectional area of the dilution passage, the second inner periphery being smaller than that of the first inner periphery and the linearly converging contoured inner wall portion is only located at a leading edge portion of the dilution passage and the inner wall of the annular grommet to or extending from the backstop is linear and parallel to the dilution passage axis from the backstop to the bottom portion of the annular grommet. ### Claim 2 (depends on 1) The wall assembly of claim 1, wherein the backstop has a curvature that matches a curvature of a portion of the dilution passage. ### Claim 3 (depends on 2) The wall assembly of claim 2, wherein the converging contoured inner wall portion converges toward the dilution passage axis. ### Claim 4 (depends on 1) The wall assembly of claim 1, wherein the backstop is arranged to be at least partially located at a trailing edge portion of the dilution passage. ### Claim 5 (depends on 1) The wall assembly of claim 1, wherein the first inner periphery and the second inner periphery define a portion of a contoured nozzle that forms local acceleration of airflow along a portion of a perimeter of the dilution passage. ### Claim 6 (depends on 1) The wall assembly of claim 1, wherein the backstop has a vortex generator. ### Claim 7 A gas turbine engine, comprising: a compressor section; a turbine section; and a combustor section, the combustor section including a wall assembly for use in a combustor of the combustor section, the wall assembly comprising: a support shell; a liner panel, the liner panel being separately secured to the support shell; and an annular grommet extending from the liner panel, the annular grommet defining a dilution passage having a dilution passage axis and the annular grommet extends through an opening in the support shell when the support shell and the liner panel are secured to each other, the annular grommet having a top portion that defines a portion of a periphery of the dilution passage; and a backstop extending from the top portion of the annular grommet, the backstop defining another portion of the periphery of the dilution passage and the backstop extending through and above the opening in the support shell when the liner panel is secured to the support shell, wherein a portion of an inner wall of the annular grommet includes a linearly converging contoured inner wall portion that extends from the top portion to a bottom portion of the annular grommet, the bottom portion being opposite the top portion and located at a hot side of the liner panel, the linearly converging contoured inner wall portion has a first inner periphery defining a portion of a first cross-sectional area of the dilution passage and a second inner periphery defining a portion of a second cross-sectional area of the dilution passage, the second inner periphery being smaller than that of the first inner periphery and the linearly converging contoured inner wall portion is only located at a leading edge portion of the dilution passage and the inner wall of the annular grommet or extending from the backstop is linear and parallel to the dilution passage axis from the backstop to the bottom portion of the annular grommet. ### Claim 8 (depends on 7) The gas turbine engine of claim 7, wherein the backstop has a curvature that matches a curvature of a portion of the dilution passage. ### Claim 9 (depends on 7) The gas turbine engine of claim 7, wherein the backstop is arranged to be at least partially located at a trailing edge portion of the dilution passage. ### Claim 10 A method of guiding airflow into a combustor of a gas turbine engine, the method comprising: locating a portion of an annular grommet in an opening of a support shell of the combustor, the annular grommet extending from a liner panel secured to the support shell, the annular grommet defining a dilution passage, the liner panel being separately secured to the support shell; and directing airflow into the dilution passage via a backstop extending from a top portion of the annular grommet, the top portion defining a portion of a periphery of the dilution passage, wherein a portion of an inner wall of the annular grommet includes a linearly converging contoured inner wall portion that extends from the top portion to a bottom portion of the annular grommet, the bottom portion being opposite the top portion and located at a hot side of the liner panel, the linearly converging contoured inner wall portion has a first inner periphery defining a portion of a first cross-sectional area of the dilution passage and a second inner periphery defining a portion of a second cross-sectional area of the dilution passage, the second inner periphery being smaller than that of the first inner periphery and the linearly converging contoured inner wall portion is only located at a leading edge portion of the dilution passage and the inner wall of the annular grommet extending from the backstop is linear and parallel to the dilution passage axis from the backstop to the bottom portion of the annular grommet. ### Claim 11 (depends on 10) The method of claim 10, wherein a periphery of the annular grommet is surrounded by a groove in the liner panel. ### Claim 12 (depends on 7) The gas turbine engine of claim 7, wherein a periphery of the annular grommet is surrounded by a groove in the liner panel. ### Claim 13 (depends on 1) The wall assembly of claim 1, wherein a periphery of the annular grommet is surrounded by a groove in the liner panel.